Field of the Invention
This invention pertains to products and methods for personal care and odor control, particularly for reducing or preventing unwanted odor from the pudendum.
Description of Related Art
Fishy odors from the pudendal region or genitalia of the female body have long been a source of annoyance and embarrassment to adult and teenaged women. Women seeking help from physicians are frequently given antibiotics such as metronidazole, based on the long-standing belief that vaginal bacteria are the cause of the problem. Indeed, a fishy odor is commonly considered to be a symptom for bacterial vaginosis (see, for example, “Bacterial Vaginosis,” Wikipedia, http://en.wikipedia.org/wiki/Bacterial_vaginosis, accessed Nov. 17, 2009). Others seeking relief have tried a variety of products such as douches which may provide only short-term decrease in the odor (if the vagina was the actual source of the odor). In spite of many medications and feminine hygiene products, there has been a long-standing unmet need in this area, fueled by lack of understanding about the causes and the nature of the problem, especially the assumption that fishy odor only arises from the vagina due to bacterial imbalance or infectious cause such as bacterial vaginosis and trichomonas. 
The “Whiff test” for vaginosis involves treating body fluids with potassium hydroxide (KOH). A resulting fishy odor produced by an amine reaction is taken as an indicator for the presence of anaerobic bacteria. However, the amine reaction or related reactions that result in a fishy odor can take place without addition of KOH, but under other elevated pH conditions on the pudendum. The materials serving as a source for the nitrogen-containing compounds released as fishy odor (e.g., trimethylamine) can include semen, blood, urine, cervical mucus and post menopausal physiologic discharge. When these are brought in contact with the anaerobic bacteria from the rectum, an unpleasant fishy odor will result. The odor is known to be associated with reactions from bacteria, but the historic focus on bacteria in the vagina and the assumption that vaginitis or more specifically, bacterial vaginosis, is the cause of the odor may have misled many in seeking for solutions that treat bacteria in the vagina.
We have found that for many women, the source of the odor is more commonly from the pudendum (including the intergluteal folds and external genitalia), where anaerobic bacteria from the lower gastrointestinal (GI) tract or other sources can be found. These anaerobic bacteria may be especially present on the external skin around the perianal anatomy.
The new recognition that vaginal bacteria are not cause of fishy odor in many women is of special significance, and helps explain why antibiotic treatments and other standard treatments have fared so poorly in treating many cases of fishy odor, and why may women presenting symptoms of fishy odor do not actually have bacterial vaginosis when thorough testing is conducted (see, for example, N. K. Lowe et al., “Accuracy of the Clinical Diagnosis of Vaginitis Compared With a DNA Probe Laboratory Standard,” Obstetrics & Gynecology, vol. 113, no. 1, January 2009, pp 89-95, abstract available online at http://journals.lww.com/greenjournal/Abstract/2009/01000/Accuracy_of_the_Clinical_Diagnosis_of_Vaginitis.15.aspx and Hope K. Haefner, “Conquering Resistant Vulvovaginitis,” 2007, presentation available online at http://www.yellowdocuments.com/12180308-advancements-in-benign-vulvar-and). It also points to the long unmet need for improved means of reducing or preventing fishy odor by better controlling the activity of anaerobic bacteria on the pudendum, particularly those interacting with or feeding on nitrogen compounds in body fluids such as semen, blood, urine, and feces.
It is believed that a particularly significant discovery is the recognition that the source of a fishy odor for many women is not bacteria in the vagina, nor bacteria coming from the vagina, but anaerobic bacteria from non-vaginal sources such as the gastrointestinal tract. An understanding of this discovery can be enhanced in part by consideration of a rare metabolic disorder, trimethylaminuria, a disorder occurring when humans have an impaired version of the enzyme flavin-containing monooxygenase 3 (FMO3), which converts trimethylamine to trimethylamine N-oxide during the metabolism of some nitrogen-containing compounds such as choline or phosphocholine. With impaired FMO3 activity, trimethylamine concentrations become elevated and strong fishy odor can be generated by the sweat and other body fluids of a person, making life difficult and painful. Foods rich in choline are especially problematic for those with trimethylaminuria, since it leads to production of large amounts of trimethylamine. Without wishing to be bound by theory, it is believed that the release of trimethyl amine and possibly other nitrogenous compounds produced by anaerobic bacteria at elevated pH on the pudendum of the human body is analogous to the production of trimethylamine in the body when oxidizing enzymes are impaired in those suffering from trimethylaminuria. Again, without wishing to be bound by theory, recognition of this analogous condition in light of the newly recognized mechanisms for fishy odor generation on the skin of the pudendum also suggests that semen may be an especially important component in the production of fishy odor in some cases, for semen, of all body fluids, may be the richest in choline and is among the richest natural sources of choline and water-soluble choline compounds, and thus is believed to be a highly significant potential source for trimethylamine production by certain anaerobic bacteria on the pudendum.
Thus, we have discovered that the introduction of semen, blood, urine, feces, and other body fluids into the pudendum, including the perineum and adjacent regions, can raise the pH on the skin and provide the nitrogenous materials and alkaline conditions for bacterial-assisted production of significant amounts of volatile amine compounds such as trimethylamine, giving rise to a fishy odor. While the reactions involved may be similar to those that occur from bacterial vaginosis, fishy odor can be produced on the pudendum under benign conditions. In other words, the vagina is not the key factor when trying to solve the problem of transient fishy odor for most women.
For effective prevention of the fishy odor from the amine reaction, wiping or washing alone is inadequate. The pH of the environment of the perianal bacteria needs to be maintained in an acidic state such as at a pH less than about 5.5, or less than about 5.3, or less than about 5.1, in order to hinder the amine reaction that causes the unwanted fishy odor. 3.5 to 4.2 is the normal range of the pH of the vagina, and a pH in this range can be suitable for the pH of the pudendum. Thus, a suitable range for pH may be, by way of example, from about 3 to about 5.5, from about 3.2 to about 5, from about 3.5 to 4.5, or from about 3.5 to 5.0. Without wishing to be bound by theory, our work indicates that the release of the fishy odor can be triggered by an amine reaction that occurs when the anaerobic bacteria of the pudendum come into contact with alkaline bodily fluids such as semen, blood, feces, and other agents such as soap, in essence, giving a positive Whiff test on the external genitalia. Possible insight into related mechanisms may be found, again without wishing to be bound by theory, in the study of Y. Tsuchiya and E. Endo, “Enzymatic Reduction of Trimethylamine Oxide,” Tohoku Journal of Agricultural Research, 1952, pp. 127-133, available online at http://ir.library.tohoku.ac.jp/re/bitstream/10097/29074/1/KJ00000713720.pdf, which describes how a bacterial enzyme, triamineoxidase, activates relatively odorless trimethylamine oxide and renders it susceptible to reduction to the highly malodorous trimethyl amine by various dehydrogenases. Several potential inhibitors of the reaction are explored. On page 130 of Tsuchiya and Endo, results for the reaction rate for trimethylamine production as a function of pH shows that a pH above 5.5 such as from about 6 to 8 favors high levels of trimethylamine, whereas a pH of 5.5 or less, or 5.0 or less, favors low levels of trimethylamine.
An understanding of the importance of maintaining a low pH in the external environment of the pudendum relative to the issue of controlling fishy odor appears to be lacking in prior attempts to deal with fishy odor. For example, some commonly used products employ baking soda, an alkaline compound, and a recognition of the role of the environment external to the vagina and its pH appears to have been lacking in terms of controlling fishy odor.
The compositions and methods proposed herein for controlling fishy odor arise in part from the surprising realization that the real problem in most cases is not bacteria in the vagina, but conditions arising from an anatomically inevitable consequence of intercourse, due to semen form intercourse, leaking urine, and blood from monthly cycles coming in contact with the perianal bacteria that can inhabit various parts of the pudendum. The close physical proximity of the vulvar and perianal regions contributes to the presence of bacteria that can produce or participate in reactions leading to generation of trimethylamine or related fishy odor compounds, feeding upon the nitrogenous compounds coming from intercourse, urine, menstruation, feces, etc.
With a realization of the nature of the origin of fishy odors due to elevated pH and associated conditions in the pudendum, we were able to subsequently develop what is believed to be the first product that addresses the real problem (for many women) over a prolonged period of time.
Vinegar wipes, douches, and other acidic products have been proposed for personal cleansing, but such products have generally been developed for rapid cleansing and not for lasting control of pH. Thus, even highly acidic vinegar wipes only provide a short-term change in pH, as the acidic components is applied and then wiped or washed off or otherwise neutralized or quickly removed from the skin. With the viscous carrier of many embodiments disclosed herein, acidifying components can be available for a prolonged period of time to effectively control the pH of the environment. Further, with larger molecular weight alpha-hydroxy acids disclosed herein (for many embodiments) that do not rapidly penetrate the skin, the alpha-hydroxy acids can remain on or above the skin to effectively maintain the pH in a suitable range for a prolonged period of time, unlike much lighter acids.
Thus, there is a need for new products and methods that can address the surprising discoveries regarding the sources of fishy odor in many women, and that can overcome the long-standing unmet needs that have not been adequately addressed by previous products, formulations, and methods.
Many retail and prescription products have been marketed are directed at treating bacteria in the vagina, which again do not address the issue of the external environment in the pudendum. Most on the retail side are a cover-up with baking soda and perfumes or other ingredients that do not address the problem or may even exacerbate it at the true source (albeit the previously unrecognized source).
The recognition that the source of the fishy odor is frequently from the pudendum and not from the vagina helps explain, in retrospect, why treatments based on attacking bacteria on the vagina have been relatively ineffective for so many women for so long, and may also help explain why misdiagnosis of vaginosis is such a common problem (see “Throwing the Dice for the Diagnosis of Vaginal Complaints?” by Andreas Schwiertz et al., Annals of Clinical Microbiology and Antimicrobials, Vol. 5. No. 4, 2006, available online at http://www.ann-clinmicrob.com/content/5/1/4). The new understanding of the need to provide long-term control of pH on the skin of the pudendum also helps explain, in retrospect, why previous solutions employing wipes and other means did not provide lasting or effective solutions. What is needed, then, is an effective system or method for providing a suitable acidic pH over a prolonged period of time in the pudendum or portions thereof such that the amine reactions giving rise to a fishy odor can be impeded, resulting in a significant decrease in the production of unpleasant odors.
In spite of the surprising discovery that a major source for fishy odor was not from the vagina itself but from the external skin of the pudendum, particularly when the pH was elevated by the presence of semen, blood, or other materials or factors, we found that various efforts to decrease pH were not necessarily adequate to provide an acceptable solution, for, among other reasons, there is a risk of skin irritation or other unwanted responses with prolonged exposure to many acidic compounds. For effective treatment of the newly appreciated causes of unwanted fish odor for many women, we have also discovered that a lasting reduction in fishy odor and associated problems of the inevitable chronic presence of anaerobic bacteria in the pudendum require new strategies to provide sustained pH control in ways that do not irritate the skin. Thus, there is a long-standing need to provide sustained pH control in non-irritating means to reduce the common problem of fishy odor production from the pudendum.
A further challenge involves body odors associated with perspiration, particularly in the pudendum. Bacteria such as Corynebacteria feed off materials in the sweat, particularly the apocrine sweat glands, and produce unpleasant odors. Such glands tend to be abundant in the groin and pudendal area. Products are available such as antiperspirants or deodorants to mask odors or reduce perspiration, but products that may be suitable for underarm use, for example, may not be safe or effective on the pudendum. In particular, the metal-containing compounds such as aluminum salts that are widely used for their ability to reduce perspiration have been the subject of as-yet unresolved concerns about their long-term health effects. Safe, effective alternatives are needed. Given the limitations in currently available products, there is a need for deodorants and antiperspirants that are effective in preventing perspiration or associated odor on the body, particularly on the pudendum, while reducing perceived health risks associated with aluminum compounds or other harsh chemicals.